(2) A graphical recording or digital printout unit shall be
completely housed in a single cabinet that shall be capable of
being locked.
(3) The chart or tape shall be so marked that each batch may be
permanently identified and so that variations in batch weights of
each type of batch can be readily observed. The chart or tape
shall be easily interpreted in increments not exceeding 0.5
percent of each batch weight.
(4) The chart or tape shall show time of day at intervals of not
more than 15 minutes.
(5) The recorder chart or tape shall become the property of the
Government.
(6) The recorder shall be placed in a position convenient for
observation by the concrete plant operator and the Government
inspector.
(7) The recorded weights or volumes when compared to the weights
or volumes actually batched shall be accurate within plus or minus
2 percent.
i. Batch Counters - The plant shall include devices for automatically
counting the total number of batches of all concrete batched and the
number of batches of each preset mixture.
[j. Rescreening Plant - A rescreening plant shall be located,
arranged, and operated in a manner that all coarse aggregate will be
routed through the plant and that its operation will ensure delivery to
the mixers of graded coarse aggregate free from variation and
conforming to the size groups and grading of paragraph AGGREGATES and
with moisture content conforming to the provisions of paragraph TESTS
AND INSPECTION. Coarse aggregate may be rescreened and delivered to
the batch plant bins one size group at a time or two or more adjacent
size groups at a time. Simultaneous rescreening of nonadjacent size
groups is not permitted. All material passing the bottom screen of the
smallest size of coarse aggregate being screened shall be wasted.]
[k. Washing Plant - All coarse aggregates shall be washed immediately
prior to entering the rescreening plant. The washing plant shall
contain adequate water nozzles and vibrating screens to remove foreign
materials and coatings from aggregate particles. Water used for
washing shall meet the requirements of paragraph WATER.]
l. Batch Plant Trial Operation - Not less than 7 days prior to
commencement of placing the test section, a test of the batching and
mixing plant shall be made in the presence of a representative of the
Contracting Officer to check operational adequacy. The number of
full-scale concrete batches required to be produced in trial runs shall
be as directed, will not exceed 20, and shall be proportioned as
directed by the Contracting Officer. All concrete produced in these
tests shall be wasted or used for purposes other than inclusion in
structures covered by this specification. All deficiencies found in
plant operation shall be corrected to the satisfaction of the
Contracting Officer prior to the start of concrete placing operations.
No separate payment will be made to the Contractor for labor or
materials required by provisions of this paragraph. Mixer uniformity
SECTION 03701
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